1. Field of the Invention
This invention relates to a printing and print inspection apparatus, and more particularly to a printing and print inspection apparatus which prints and at the same time, inspects printed matter in the form of image read data to sort out only acceptable printed sheets.
2. Description of the Related Art
A printing and inspection method of printing and at the same time, inspecting printed matter in the form of image read data to sort out only acceptable printed sheets has been disclosed in Jpn. Pat. Appln. KOKOKU Publication 4-24228. With the method of inspecting printed matter disclosed in the publication, when the difference between the read-out image data and the reference value has exceeded a preset value, the area is judged to be an error point in the printed matter, and the printed matter is determined to be unacceptable on the basis of the number of error points.
Conventional printing apparatuses with a print inspection and sorting function have widely used a method of sensing defects by density comparison as a printed matter inspection method. With this printing method, since printed matter is sorted out on the basis of the result from the sensing process, when an object containing minute defects or faint defects is inspected, there may be no difference in the sense result between variations in the variable range of acceptable print and actual defects. In this state, in making a highly reliable inspection, an attempt to sort out printed sheets with minute defects and faint defects as defective printed sheets permits part of the acceptable printed sheets with no difference in the sense result to be discarded as defective printed sheets. As a result, the number of sheets of acceptable printed matter decreases, leading to a reduction in the yield of printing and a higher cost.